Analysis and Development of Performance-Based Requirements for Railroad Tank Cars

2014 ◽  
Author(s):  
Steven W. Kirkpatrick ◽  
Robert A. MacNeill ◽  
Francisco Gonzalez
Keyword(s):  
Structural Integrity ◽  
The United States ◽  
Impact Testing ◽  
Impact Behavior ◽  
Safety Regulations ◽  
Significant Research ◽  
The Government ◽  
Current Impact ◽  
Test Requirements ◽  
The Impact

There has been significant research in recent years to analyze and improve the impact behavior and puncture resistance of railroad tank cars. Ultimately, the results of this work will be used by the Government regulatory agencies in the United States and Canada to establish performance-based testing requirements and to develop methods to evaluate the crashworthiness and structural integrity of different tank car designs. This paper describes analyses of current impact testing requirements and impact test methodologies using detailed finite element analyses (FEA). The results of these analyses are used to identify characteristics of the test methodologies that are desirable or undesirable for the test requirements in future tank car safety regulations.

Side Impact Testing and Analyses of Unpressurized Tank Cars

2015 ◽  
Author(s):  
Steven W. Kirkpatrick ◽  
Robert A. MacNeill ◽  
Francisco Gonzalez ◽  
Przemyslaw Rakoczy
Keyword(s):  
Structural Integrity ◽  
The United States ◽  
Impact Testing ◽  
Side Impact ◽  
Impact Response ◽  
Impact Behavior ◽  
Pressure Tank ◽  
The Government ◽  
Tank Pressure ◽  
The Impact

There has been significant research in recent years to analyze and improve the impact behavior and puncture resistance of railroad tank cars. Ultimately, the results of this work will be used by the Government regulatory agencies in the United States and Canada to establish performance-based testing requirements and to develop methods to evaluate the crashworthiness and structural integrity of different tank car designs. This paper describes results of recent side impact testing and corresponding analyses using detailed finite element analyses (FEA). The test and analyses were performed to evaluate the side impact puncture performance of DOT-111 tank cars. The tank car was filled with water to approximately 97 percent of the volume. The tank was then sealed but not pressurized. The tank car was impacted at the Transportation Technology Center, Inc. by a 297,125-pound ram car with 12-by 12-inch ram head fitted to the ram car impacted the tank center. The analyses were on overall good agreement with the measured impact response. The lading was found to play a more significant role in the impact response than in previous testing and analyses of pressure tank cars. This is not surprising considering the reduced structural stiffness of the tanks compared to thicker pressure tank cars and the reduced effective stiffness from the initially unpressurized tank at impact. The smaller outage volume also contributes to a dramatic increase in the tank pressure as the dent formation reduces the tank volume and compresses the contents of the tank.

Tank Car Puncture Analyses for Various Impactors and Impact Conditions

2013 ◽  
Author(s):  
Steven W. Kirkpatrick ◽  
Francisco Gonzalez ◽  
Karl Alexy
Keyword(s):  
Finite Element ◽  
Research Program ◽  
Impact Testing ◽  
Impact Behavior ◽  
Finite Element Analyses ◽  
Damage And Failure ◽  
Wide Range ◽  
Significant Research ◽  
Detailed Simulation ◽  
The Impact

There has been significant research in recent years to analyze and improve the impact behavior and puncture resistance of railroad tank cars. Much of this research has been performed using detailed nonlinear finite element analyses supported by full scale impact testing. This use of detailed simulation methodologies has significantly improved our understanding of the tank impact behaviors and puncture prediction. However, the evaluations in these past studies were primarily performed for a few idealized impact scenarios. This paper describes a research program to evaluate railroad tank car puncture behaviors under more general impact conditions. The approach used in this research program was to apply a tank impact and puncture prediction capability using detailed finite element analyses (FEA). The analysis methodologies apply advanced damage and failure models that were validated by series of material tests under various loading conditions. In this study, the analyses were applied to investigate the tank puncture behaviors for a wide range of impact conditions.

Development of Analytical Models for Railroad Tank Car Impact and Puncture Behaviors

2012 ◽  
Author(s):  
Steven W. Kirkpatrick ◽  
Joseph M. Munaretto ◽  
Virginia Phan ◽  
Robert A. MacNeill
Keyword(s):  
Full Scale ◽  
Impact Testing ◽  
Analytical Models ◽  
Impact Behavior ◽  
Wide Range ◽  
Significant Research ◽  
Detailed Simulation ◽  
Puncture Force ◽  
Tank Geometry ◽  
The Impact

There has been significant research in recent years to analyze and improve the impact behavior and puncture resistance of railroad tank cars. Much of this research has been performed using detailed nonlinear finite element analyses supported by full scale impact testing. This use of detailed simulation methodologies has significantly improved our understanding of the tank impact behaviors and puncture safety. However, the performance of the detailed analyses or full scale testing can require significant computer or financial resources to evaluate a wide range of impact scenarios. This paper describes the development of analytical models that can predict the impact and puncture behavior of a pressurized railroad tank car. The methodology applied is to first develop a model that can predict the force-deflection behavior obtained from a general impact at any point on the tank. Separately, a characteristic puncture force is determined as a function of the tank geometry, impactor geometry, and impact conditions. Combined, these models can be applied to predict the impact and puncture behavior of the tank.

Proposed Methodology Changes to Determine Minimum Design Metal Temperature of ASME/API Impact Tested Materials Based on Fracture Mechanics

2018 ◽  
Author(s):  
Seetha Ramudu Kummari ◽  
Brian Macejko ◽  
Phillip E. Prueter
Keyword(s):  
Fracture Mechanics ◽  
Impact Test ◽  
Base Material ◽  
Impact Testing ◽  
Metal Temperature ◽  
Historical Background ◽  
Relative Indication ◽  
Current Impact ◽  
Test Requirements ◽  
The Impact

For equipment designed to ASME or API standards, it is common practice to perform impact testing of base material and/or weldments to establish the Minimum Design Metal Temperature (MDMT). The impact test is typically a Charpy V-Notch (CVN) test and the test temperature is set equal to the MDMT. The required Charpy energy at MDMT can vary anywhere from 10 ft-lbs to 40 ft-lbs depending on material specification, thickness, and the ASME/API standard. The detailed historical background behind the Charpy energy requirements of different ASME/API standards is not well documented. Additionally, no credit is given for post weld heat treatment (PWHT) of impact tested materials. The CVN tests are used because they are quick and economical for quality control, but the tests only provide a relative indication of material toughness. Consequently, the current impact test requirements lead to inconsistent results in brittle fracture assessments, conducted through explicit fracture mechanics. In this paper, two examples are presented to highlight the inconsistencies of the current impact test requirements. A methodology of estimating MDMT for impact tested materials based on fracture mechanics, consistent with Welding Research Council (WRC) Bulletin 562 [1] is also presented. Furthermore, this methodology explicitly accounts for the effects of PWHT (and the influence of weld residual stress on crack driving force) for impact tested materials. A methodology of adjusting MDMT for in-service impact tested materials is also presented. In the interest of moving towards harmonizing the impact test requirements, an alternative procedure for establishing impact test requirements is presented for ASME/API consideration.

scholarly journals Effects of temperature and impactor nose diameter on the impact behavior of PA6 and PP thermoplastic composites

2018 ◽  
Vol 51 (1) ◽  
pp. 64-74 ◽  
Author(s):  
Akar Dogan ◽  
Yusuf Arman
Keyword(s):  
Load Capacity ◽  
Testing Machine ◽  
Polyamide 6 ◽  
Impact Testing ◽  
Impact Behavior ◽  
Thermoplastic Composites ◽  
Test Machine ◽  
Effects Of Temperature ◽  
Impact Energies ◽  
The Impact

In this study, the effects of temperature and impactor nose diameter on the impact behavior of woven glass-reinforced polyamide 6 (PA6) and polypropylene (PP) thermoplastic composites were investigated experimentally. Impact energies are chosen as 10, 30, 50, 70, 90, 110, 130, and 170 J. The thickness of composite materials is 4 mm. Impact tests were performed using a drop weight impact testing machine, CEAST-Fractovis Plus, and the load capacity of test machine is 22 kN. Hemispherical impactor nose diameter of 12, 7, and 20 mm were used as an impactor. The tests are conducted at room temperature (20°C and 75°C). As a result, the PP composites of the same thickness absorbed more energy than PA6 composites. The amount of absorbed energy of PP and PA6 composites decreased with temperature.

The Impact of the Nicaragua Case on Matters of Evidence and Fact-Finding

2012 ◽  
Vol 25 (1) ◽  
pp. 149-156
Author(s):  
PAUL S. REICHLER
Keyword(s):  
United States ◽  
Armed Conflict ◽  
The United States ◽  
Pulp Mills ◽  
Government Officials ◽  
The Government ◽  
Fact Finding ◽  
Day To Day Operations ◽  
High Level ◽  
The Impact

AbstractThe Nicaragua case demonstrates the Court's competence in receiving and interpreting evidence, and in making reasoned findings of fact, even in the most complicated evidentiary context, as is often presented in cases involving use of force and armed conflict. The Court applied well-established standards for evaluating the conflicting evidence presented to it. In particular, the Court determined that greater weight should be given to statements against interest made by high-level government officials than to a state's self-serving declarations. The Court also determined that statements by disinterested witnesses with first-hand knowledge should receive greater weight than mere statements of opinion or press reports. In applying these guidelines, the Court found, correctly, that (i) the United States had used military and paramilitary force against Nicaragua both directly and indirectly, by organizing, financing, arming, and training the Contra guerrillas to attack Nicaragua; (ii) the evidence did not support a finding that the United States exercised direct control over the Contras’ day-to-day operations; and (iii) there was no evidence that Nicaragua supplied arms to guerrillas fighting against the government of El Salvador during the relevant period, or carried out an armed attack against that state. While Judge Schwebel's dissent criticized the last of these findings, in fact, the evidence fully supported the Court's conclusion. In subsequent decisions during the past 25 years, the Court has continued to rely on the approach to evidence first elaborated in the Nicaragua case and has continued to demonstrate its competence as a finder of fact, including in cases involving armed conflict (Bosnia Genocide) and complex scientific and technical issues (Pulp Mills).

scholarly journals SUBPRIME MORTGAGE CRISIS IN THE UNITED STATES IN 2007–2008: CAUSES AND CONSEQUENCES (PART I)

Ekonomika ◽  
2015 ◽  
Vol 93 (4) ◽  
pp. 85-118 ◽  
Author(s):  
Vaidotas Pajarskas ◽  
Aldona Jočienė
Keyword(s):  
United States ◽  
Federal Reserve ◽  
The United States ◽  
Mortgage Market ◽  
Subprime Mortgage ◽  
Market Expansion ◽  
Mortgage Crisis ◽  
Subprime Mortgage Crisis ◽  
The Government ◽  
The Impact

The main purpose of this article is to determine which factors and how contributed to the subprime mortgage crisis in the United States in 2007–2008, what their causal links and effects on the markets and the whole economy were, and to assess what actions could have been taken by the Federal Reserve and the Government in order to mitigate or prevent the consequences of subprime mortgage crisis and housing bubble. In order to obtain the research results, the authors performed a qualitative analysis of the scientific literature on the course of events and their development that led to the subprime mortgage crisis, and focused on the insufficiently regulated home mortgage market expansion, the impact on the subprime mortgage crisis of financial innovations and financial engineering, poorly evaluated systemic risks and policy undertaken by both the U.S. Government and the Federal Reserve before and after the crisis. The quantitative research focused on two main parts: firstly, analysis of the dependence between the causes of subprime mortgage crisis and the consequences, using a statistical and regression analysis, and secondly, an alternative path the Government and the Federal Reserve could have taken in their policy actions and the results they could have produced. The authors believe that the results of the research could give useful guidelines to the central bankers and government officials on how to make long-term decisions that can help in preparing for the financial distress, mitigating the consequences when the crisis strikes, accelerating the recovery and even preventing the crisis it in the future. The second part of the qualitative research will appear in the next issue of the journal.

scholarly journals Warlords, the United States, and the state of anarchy in Afghanistan

2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Ahmad Shah Azami
Keyword(s):  
United States ◽  
The United States ◽  
State Building ◽  
The State ◽  
Negative Consequences ◽  
Human Rights Abuses ◽  
Illegal Mining ◽  
The Us ◽  
The Government ◽  
The Impact

As part of its “War on Terror”, the United States (US) provided immense sums of money and advanced equipment to Afghan warlords in order to defeat and dismantle the Taliban and al-Qaeda in Afghanistan. Nearly two decades after the 2001 US-led intervention in Afghanistan that toppled the Taliban regime, the US continues supporting the warlords in various ways. As the intervention was also aimed at establishing a functioning state and reconstruction of the war-torn country, the US needed the support of local warlords to achieve its goals. However, over time, warlords and warlordism became a major challenge to the postTaliban state-building project and in many ways undermined the overall security and the state monopoly on violence. These warlords, who had been mostly expelled and defeated by the Taliban regime, returned under the aegis of the B52 bombers, recaptured parts of the country and reestablished their fiefdoms with US support and resources. They not only resist giving up the power and prestige they have accumulated over the past few years, but also hamper the effort to improve governance and enact necessary reforms in the country. In addition, many of them run their private militias and have been accused of serious human rights abuses as well as drug trafficking, arms smuggling, illegal mining and extortion in the areas under their control or influence. In many ways, they challenge the government authority and have become a major hurdle to the country’s emerging from lawlessness and anarchy. This paper explores the emergence and reemergence of warlords in Afghanistan as well as the evolution of chaos and anarchy in the country, especially after the US-led intervention of late 2001. It also analyzes the impact of the post-9/11 US support to Afghan warlords and its negative consequences for the overall stability and the US-led state-building process in Afghanistan.

The Impact of Mesh Implantation on Vaginal Smooth Muscle Innervation and Contraction

2013 ◽  
Author(s):  
Zegbeh C. Jallah ◽  
Pamela Moalli ◽  
Andrew Feola ◽  
William Barone ◽  
Stacy Palcsey ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Surgical Repair ◽  
The United States ◽  
Pelvic Organ ◽  
Muscle Innervation ◽  
Vaginal Canal ◽  
The Cost ◽  
Vaginal Smooth Muscle ◽  
The Impact

Pelvic organ prolapse (POP) is a multifactorial disorder characterized by the descent of the pelvic organs into the vaginal canal. This disorder is associated with decreased quality of life, and even depression, yet 50% of women over the age of fifty are living with POP. The cost associated with the repair of POP exceeds one billion dollars annually, in the United States alone. This rather exorbitant figure includes the cost of surgery performed for symptom management, but does not include strategies which address the underlying cause of the disorder for which there are none. Because failure rates of native tissue repairs are as high as 30%, vaginal mesh is increasingly used in the surgical repair of POP. The procedure aims to reinforce the fibromuscular layer of the vagina and the paravaginal attachments, thus providing structural integrity to the weakened native tissues. However, the use of mesh is limited by mesh-related complications including exposure, erosion, pain contraction and infection.

Effects of UV Light and Moisture Absorption on the Impact Resistance of Three Different Carbon Fiber-Reinforced Composites

2014 ◽  
Author(s):  
V. Patlolla ◽  
J. George ◽  
Soo-Han Loo ◽  
R. Asmatulu
Keyword(s):  
Carbon Fiber ◽  
Moisture Absorption ◽  
Uv Light ◽  
Load Capacity ◽  
Contact Angles ◽  
Impact Testing ◽  
Impact Response ◽  
Uv Exposure ◽  
Impact Behavior ◽  
The Impact

The purpose of this research was to determine the influence of material properties on the impact response of a laminate, whereby specimens were fabricated and cured under a vacuum and high temperature using three types of pre-impregnated (prepreg), carbon fibers, namely unidirectional fiber, plain weave woven fiber, and non-crimp fiber (NCF). Each carbon fiber panel, usually known for its low-impact properties, of 16 plies underwent impact testing using a low-velocity impactor and visual damage inspection by C-scan in order to measure the damage area and depth, before and after impact testing. These panels were treated with UV exposure and moisture conditioning for 20 days each. Water contact angles were taken into consideration to determine the hydrophobicity and hydrophillicity of the respective prepreg materials. Experimental results and damage analysis showed that UV exposure and moisture conditioning showcased the variation in impact response and behavior, such as load-carrying capacity, absorbed energy, and impact energy of the carbon fiber panels. This study illustrates that non-crimp carbon fiber laminates were far more superior relative to load capacity than woven and unidirectional laminates, with the NCF-AS laminate exhibiting the highest load capacity of 17,244 lb/in (pre-UV) with only 0.89% decrease after UV exposure. This same laminate also had a 1.54% decrease in sustaining impact and 31.4% increase in wettability of the panel. Moreover, the study shows how symmetric and asymmetric stacking sequences affect the impact behavior of non-crimp fiber laminates. These results may be useful for expanding the capacity of carbon fiber, lowering costs, and growing new markets, thus turning carbon fiber into a viable commercial product.

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